1. Field of the Invention
The invention relates to an electronic circuit, and more particularly to an oscillator module and a reference circuit thereof.
2. Description of Related Art
FIG. 1 is a schematic diagram of a conventional oscillator circuit. FIG. 2 shows voltage waveforms of nodes A and B and a clock signal CLK of the conventional oscillator circuit. Referring to FIG. 1 and FIG. 2, the conventional oscillator circuit 110 is configured to generate a temperature insensitive clock signal CLK based on an input current IIN and a reference voltage VREF. During a period Ta, a capacitor CA is charged by the input current IIN, such that the voltage of the node A increases to the reference voltage VREF, and the clock signal CLK stays at a high level in the meanwhile. Until the voltage of the node A is substantially equal to the reference voltage VREF, an RS flip-flop 112 is triggered, and then a current path that a capacitor CB is charged is conducted. Accordingly, the voltage of the node B is charged by the input current IIN and increases to the reference voltage VREF during a period Tb. The clock signal CLK stays at a low level during this period. Until the voltage of the node B is substantially equal to the reference voltage VREF, the RS flip-flop 112 is triggered again, and then the capacitor CA is charged by the input current IIN. The foregoing operation is repeated as time goes on, and thus the oscillator circuit 110 outputs the temperature insensitive clock signal CLK with a period T.
In order to generate a temperature insensitive clock signal, a reference circuit of the oscillator circuit (not shown) must provide a temperature insensitive input current and a temperature insensitive reference voltage to the oscillator circuit. However, for providing the temperature insensitive input current, an extra circuit design for the reference circuit is necessary. As a result, extra circuit area and power are consumed in the conventional reference circuit.